Playing With Fire
by GoldGuardian2418
Summary: Sans and Frisk go see Grillby in order for Sans to get some revenge on the fire monster. Done as a request for EmeraldMoonGreen. :)


**EmeraldMoonGreen asked for this one. Here you go, Amiga! Enjoy! :)**

 **Undertale belongs to Toby Fox. I own nothing.**

 **A/N: This story is the sequel to "Friends Can Lift Your Burdens."**

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 **Playing With Fire**

Sans and Frisk appeared in the back room of Grillby's, quickly hunkering down to wait for the fire monster. "Okay, get ready, kiddo," said Sans. "Grillby's closing and locking the doors for the night."

Frisk checked her phone and saw it was nine o'clock. "How did you convince Mom to let me stay up past my bedtime?" She whispered to him.

Sans grinned. "She told me that you didn't have school tomorrow, as it's almost Easter," he said. "So I convinced her to let you come to our house for a sleepover and with Undyne staying late to do paperwork and Pap helping her, it's the perfect chance to get revenge on Grillby."

The brown-haired girl giggled again, but then grew serious. "Dunkle Sans, you should have told me that you were having nightmares about those Resets," she said.

He gently ruffled her hair. "I know, kiddo," he said. "But I didn't want you feeling guilty, especially when you weren't the cause of my nightmares. Grillby reminded me that I shouldn't hide it from my family."

Frisk nodded with a grin. "By tickling you to pieces," she said with another giggle.

Sans gently tapped her nose. "And only you know about that," he said half-warningly. "Not a word to anyone else, or you'll be the one getting tickled to pieces."

She wordlessly nodded and they heard Grillby coming to the back room and hid, waiting patiently as the fire monster came into view and let out a deep sigh, indicating it had been a long, tiring day as he sat down on the couch before laying down to rest a moment.

The hidden skeleton softly snapped his fingers, his telekinesis wrapping around Grillby, who sensed it too late and was quickly restrained to the couch by the blue telekinesis and Frisk popped out from under the couch, standing next to the trapped monster. "Frisk?" He said. "What are you doing back here?"

She giggled as Sans stepped into view, one hand glowing blue along with his left eye. "She and I came to pay you a visit, Grillbz," he said. "A ticklish visit."

Grillby gave him an incredulous look and Frisk looked at Sans. "Is he ticklish?" She asked curiously.

Sans grinned at her. "As humans say, only one way to find out, right?"

The young girl grew thoughtful and climbed up on the couch, sitting on the fire monster's stomach and cocking her head to the side curiously before shrugging and deciding to try Grillby's underarms first, and as soon as her fingers poked there, the trapped monster flinched hard, an almost-stifled laugh escaping him, making Sans grin and strengthen his telekinesis on his friend. "You've struck gold, kiddo," he said to Frisk. "That must be his major tickle spot."

Grinning, the brown-haired girl wiggled her fingers into the fire monster's underarms, the instant laughter coming out of Grillby telling both her and Sans that their friend's underarms were indeed his most ticklish spot and Frisk began tickling the sensitive underarms faster.

"NOHOHOHOHOHOHOHOHO! FRISK! AHAHAHAHAHAHAHAHA!" Grillby laughed out.

She giggled and saw the short skeleton come up to them. "Bet two of us tickling his underarms will put him in stitches," he said, making her giggle again.

The fire monster couldn't even protest as four hands now tickled his underarms while Sans' telekinesis kept him pinned and he laughed his hardest, unable to squirm as the telekinesis had him in a firm hold and the twenty fingers covered every spot of his ticklish underarms.

"AHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHA!"

The two ticklers grinned at this and gave their friend a small break when they saw his face start to turn a light blue. Frisk then looked at Sans. "I bet he's a squirmer, Dunkle Sans," she said with a giggle.

He grinned. "Let's put that thought to the test," he said, pulling away some of his telekinesis, but not too much so that Grillby was still restrained. Giggling again, Frisk began tickling the restaurant owner's sides without warning.

Turns out, Grillby was a squirmer, unable to keep still as the child mercilessly sought out his other tickle spots, giggling the entire time while Sans kept the fire monster pinned and helped the child when she tickled their friend's stomach and then his knees. From the wiggle worm Grillby was rapidly becoming, the two ticklers guessed that their victim was indeed very ticklish and having one person tickle him was bad enough, but when two were tickling him, it was driving him crazy.

"AHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHA!"

The joke-loving skeleton and ten-year-old girl grinned hugely, merciless in the tickle torture as Frisk then crawled up to Grillby's neck, burying her face into his neck and blowing a raspberry there. "EEK!"

The unmanly squeak that left Grillby had Frisk in stitches as she laughed hard and Sans chuckled. "Well, well, what was that we heard, hmm?" He asked teasingly.

Frisk blew another raspberry into Grillby's neck, forcing him to let out another unmanly squeak, which made the skeleton chuckle again as he got a sneaky idea and carefully tugged Grillby's shirt up enough to expose the fire monster's stomach and he followed Frisk's lead by blowing raspberries into the exposed stomach.

The unmanly squeak Grillby let out before now became an unmanly squeal. "NOHOOHOHOHOHOHO! PLEAHEEHEEHEEASE! MERCY!" He begged them.

"What do you think, Frisk?" Sans asked with a mischievous smile.

"Tickle him more!" She said with a giggle.

"Okay, then."

The fire monster was once again at their mercy and they went in for the ultimate tickle torture with Frisk blowing raspberries into the trapped monster's neck while she tickled his underarms and Sans mimicking the girl's attacks on his friend's stomach and sides.

Frisk suddenly noticed that it her hands were starting to feel like they were getting slightly burned and she sat up to see Grillby's shirt was smoking as was the rest of him. "Dunkle!" She called out warningly.

Sans, seeing why she had cried out, quickly grabbed Frisk and snapped his fingers, dispelling his telekinesis. Grillby, now able to move, quickly got off the couch and lay down on the tile floors, a sizzling sound coming from him as the cold tile counteracted with the heat his body had produced. "So that's why he keeps the air-conditioner on all the time in the back room," the joke-loving skeleton said thoughtfully.

Frisk looked at him. "Is Grillby okay, Dunkle?" She asked worriedly.

Sans really hoped so and after hearing the sizzling die down, he kneeled beside his friend. "Grillbz? You okay, buddy?" He asked.

Grillby groaned a little as he sat up, taking a few deep breaths as he straightened out his shirt. Seeing Frisk looking at him worriedly, he smiled and carefully stood up before he scooped up Frisk in his arms and playfully, but gently, punched Sans' shoulder. "Spread this around and I'll make you squeal even louder than I did," he said, making the young girl giggle. "That goes for you too, Frisk."

"Yes, Mr. Grillby," she said.

"Don't get your flames out of place, Grillbz," Sans said. "Our lips are sealed."

"If they were, you wouldn't be talking," said the fire monster, making both his friends laugh at that and he sighed. "Well, you two did help me feel better, so I guess I can forgive you."

The skeleton looked up at him, sensing something. "Grillby, what happened?" He asked seriously.

"The health inspector came in, demanding to see and test the food I make here and it took him three hours before he was satisfied and then the police arrived with the report someone had accused me of burning them, but it turned out that was just a crank call, and on top of that, I had five very rude customers today," Grillby explained.

Frisk looked saddened. "No wonder you looked so tired," she said, wrapping her arms around his neck in a hug and he smiled as he returned the hug.

"Want me to teach those rude customers a lesson?" Sans asked, his voice going low and his hands starting to glow.

"Some of my other customers and Greater Dog beat you to it," said the fire monster. "Someone even filmed the whole thing from the rude customers' words to them being chased out by the other customers and Greater Dog warning them not to come back."

Sans' phone rang and he answered it when he saw Alphys' number. "What's up, Alphys?" He asked and listened to the scientist. "Whoa. That many hits? And it's only been up for an hour? I'll let Grillby know."

He turned to the other two. "That customer posted that video online and it's racked up quite a few hits, something like a billion hits and check out the comments," he said, pulling up the video on his phone.

One compliment actually made the three smile. 'Grillby's is the hottest place in town. Those jerks had no right to be rude to the guy that helps the fire department in his free time', it said.

Frisk looked at him. "You help the fire department?" He asked.

Grillby smiled and pointed to a plaque on a nearby wall, to which they saw was an award for helping the fire department and it was dated a couple months prior. "When you freed us and I was looking through town for this building to set up my restaurant, there was a fire at a nearby house and while the family was out, one of the firefighters had fallen and been trapped under some debris, which caught fire and blocked the other firefighters from going to rescue their fellow firefighter. I quickly went in and got him out, seeing that he was attended to by paramedics before heading back here. A couple days later, all the firefighters came here to eat and the captain gave me that plaque and even pitched in to pay the loan I had taken out to open this place up and they've even taken it upon themselves to promote my restaurant," he said.

"That's great, Grillbz," said Sans as Frisk hugged Grillby again.

"Thank you both," he said. "You two just reminded me that my friends and the good customers outnumber the rude ones."

They smiled and helped their friend lock up for the night before Grillby headed home and Sans picked up Frisk and teleported home, seeing the young girl was sleepy. "You were the tickler and you still got worn out, huh, kiddo?" He said.

She giggled. "Yeah," she said. "But it was fun."

He nodded as he put her to bed and was about to go to bed himself when a text came in and he saw it was a picture of him, Grillby, and Frisk smiling at the camera and the text was from Toriel. _'Heard from Grillby that you and Frisk helped him and he asked me to send you this picture,'_ it said.

Sans smiled, seeing it was Toriel's way of saying she wasn't mad that the skeleton let Frisk stay up later than usual and on top of it, Grillby was feeling better too. "Looks like my 'revenge' was just what he needed," he said to himself with another chuckle, the events playing in his mind again before he went to sleep for the night.

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 **Please leave a review, but no flames!**

 **GoldGuardian2418**


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